Evaluation of the 7-day physical activity recall in urban and rural men

PURPOSE: To assess reliability and validity of the 7-d physical activity recall (PAR) in 60- to 80-yr-old men from urban and rural homes in the southeastern United States. METHODS: Two hundred twenty 60- to 80-yr-old men (29% minority ethnicity) from Veterans Affairs primary care clinics completed two PAR interviews at 2- to 4-wk intervals. The PAR included modifications to elicit and score light-moderate (2-3 METs) as well as moderate (3-6 METs) and hard (>/=7 METs) physical activity. Reliability was assessed using intraclass correlations from the two interviews. Validity was assessed using Spearman correlations of PAR variables with 6-min walk performance, and with treadmill performance and accelerometer activity counts from subsamples, as well as measures of gait, balance, activities of daily living, and perceived quality of life. Results were examined separately for urban and rural participants. RESULTS: Reliability coefficients were acceptable and PAR measures of estimated energy expenditure, and time spent in hard, moderate, and light-moderate activity correlated as hypothesized with the fitness and health measures. CONCLUSION: Reliability and validity coefficients were generally similar to those found in studies of the PAR with younger samples and with instruments designed specifically for use with elders. The PAR is a useful and flexible instrument for assessing physical activity of varying intensity in older men living in both urban and rural home settings.     

A comparison of the Yale Physical Activity Survey with other physical activity measures

PURPOSE: The purpose of this study was to determine associations of the Yale Physical Activity Survey (YPAS) with the Stanford 7-d physical activity recall (PAR) and several physiologic measures, both cross-sectionally and longitudinally. METHODS: Participants were 59 individuals (45% African-American, 79% women) between the ages of 60 and 80 yr who were enrolled in a clinical trial. From the YPAS, total time in activity, estimated weekly energy expenditure, and indices of vigorous activity, leisurely walking, moving, standing, sitting, and an overall summary index were determined. From the PAR, daily energy expenditure, and hours spent in light, moderate, and hard/very hard activities were estimated. Physiologic measurements included estimated VO2max, resting pulse rate, and body mass index (BMI). RESULTS: Weekly energy expenditure, total time in activity, and the summary index correlated with daily energy expenditure at baseline (Spearman correlations = 0.37, 0.30, 0.33, respectively, Ps < 0.01) and time in moderate activity (r = 0.37, 0.29, 0.39, Ps < 0.01). The vigorous index was also significantly correlated with daily energy expenditure and time in light, moderate, and hard/very hard activity. The summary, moving, and standing indices correlated with VO2max (Ps < 0.05) and BMI (Ps < 0.05). Change in physical activity determined from the PAR correlated with change in most YPAS dimensions, although few correlations were statistically significant. CONCLUSIONS: The global activities and the vigorous activity index determined from the YPAS correlated with corresponding measures of the PAR. The validity of the YPAS for light-intensity activities is less clear, although optimal validation measures for light-intensity activity are yet to be defined. The ability of the YPAS to detect change in physical activity shows some promise, but data from this study are insufficient to be conclusive.     

Validation of the PDPAR as an adolescent diary: effect of accelerometer cut points

PURPOSE: To evaluate the validity of the Previous Day Physical Activity Recall (PDPAR) as a physical activity diary in adolescents using two accelerometer intensity classifications. METHODS: One hundred eighth graders (47 boys, 53 girls) used the PDPAR as a daily diary and wore MTI accelerometers for four consecutive days. Measured time spent in moderate (> or = 3 METs) and vigorous (> or = 6 METs) activity was based on two published MTI cut-point limits (that of Freedson et al./Trost et al. and that of Puyau et al.). Spearman rank order correlations and Bland-Altman plots were used to examine agreement between MTI and PDPAR diary estimates of activity. RESULTS: MTI estimates of mean minutes per day of total moderate to vigorous physical activity (MVPA) were 65.2 (+/-43.2) using the Freedson et al./Trost et al. cutoffs and 17.5 (+/-18.5) using those of Puyau et al., while students self-reported 105.1 (+/-80.1) min.d(-1). Significant relationships were observed between the diary and MTI for total MVPA using either the Freedson et al./Trost et al. (r = 0.42) or Puyau et al. (r = 0.41) cutoff as well as raw counts (r = 0.44). Plots showed reasonable agreement between the diary and Freedson et al./Trost et al. MTI estimates of MVPA for daily totals of < or = 60 min, but the Puyau et al. estimates were consistently lower. Diaries overestimated activity as time increased when compared to either MTI cut point, especially on vigorous activity. CONCLUSIONS: Time estimates of MVPA differed by assessment tool, but diary estimates showed adequate association with the MTI. Diaries reflected intensity-specific activity, corresponding most closely with the Freedson et al./Trost et al. classification of moderate, but substantially overestimated vigorous activity regardless of cut-point method. This is likely due to the measurement characteristics of the PDPAR, which classifies activities in 30-min blocks, as well as the nature of common activities in which high levels of intensity are not sustained.     

Youth recall and TriTrac accelerometer estimates of physical activity levels

PURPOSE: To examine significance of missing data and describe physical activity patterns using recall and accelerometer measures among youth in a nonlaboratory setting. METHODS: Fifty-four middle-school students wore TriTrac-R3D monitors (TTM) and completed an interviewer-prompted 24-h recall during two, 5-d monitoring sessions. We coded 2860 30-min recall intervals to a standard MET compendium. Complete TTM data were gathered for 43 students. Ordinal multinomial models tested for bias in TTM estimates of activity levels due to: 1) exclusion of subjects with incomplete TTM data, and 2) exclusion of intervals within days due to missing TTM data. RESULTS: Students with complete monitor data had an average 12.5 +/- 0.9 monitored hours per day over 5.5 +/- 2.1 d. Compared with students with incomplete monitoring data, they reported similar proportions of recall 30-min intervals at sedentary (68% vs 69%), light (14% vs 15%), moderate (11% vs 10%), and vigorous (7% vs 6%) intensity levels (P = 0.63). The proportion of recall intervals (within days) with and without simultaneous monitoring data did not differ by activity intensity (P = 0.64) across sedentary (69% vs 67%), light (14% vs 12%), moderate (11% vs 10%), and vigorous (6% vs 9%) categories. Recalls overestimated percent time per day in moderate and vigorous activity relative to TTM (22.8% vs 8.9%, P < 0.0001). Boys reported higher percent of time than girls in vigorous activity (10.9% vs 3.9%, P < 0.05). Girls reported more time than boys (9.5% vs 6.4%, P < 0.05) in light activities. No significant sex differences were observed using TTM. CONCLUSIONS: Missing TTM data did not bias estimates of activity levels. Self-reported activity measures overestimated moderate and vigorous activity relative to the TTM and varied by sex.     

Comparisons of four methods of estimating physical activity in adult women

PURPOSE: To compare four different methods of measuring physical activity (PA) in adult women under free-living conditions. METHODS: Twelve women participated in a 7-d period during which PA was assessed via self-report, accelerometry and step-counting. Subjects wore at the waist a Tritrac-R3D accelerometer, a Computer Science Application Inc. activity monitor (CSA), both of which measure bodily accelerations in various planes, and a Yamax Digi-Walker-500 that records steps. After the 7-d period subjects responded to a 7-d Physical Activity Recall interview (PAR). Results: Physical activity-related energy expenditure (PAEE) determined from PAR was significantly higher than PAEE estimated from either the Tritrac, CSA, or the Yamax data. Time spent in light, moderate, and hard physical activity was not significantly different between PAR, CSA, and Tritrac. Log-transformed activity counts from CSA were highly correlated with log-transformed Tritrac results (r > 0.90). Number of steps recorded by the Yamax was significantly correlated with untransformed Tritrac and CSA results. CONCLUSIONS: Based upon comparisons with PAR, Tritrac, CSA, and Yamax underestimate the amount of PAEE by 25, 46, and 48%, respectively. The correspondence between the Tritrac and CSA results suggests that both devices produce similar estimates of bodily movement in free-living women. The relationships among results for Tritrac, CSA, and Yamax indicate that the number of steps recorded by the Yamax is representative of the amount of physical activity performed during the day as estimated by Tritrac and CSA. These results should be useful when selecting a method to measure PA in individuals under free-living conditions.     

Habitual physical activity, strenuous exercise, and salivary immunoglobulin A levels in young adults: the Amsterdam Growth and Health Study

Secretory IgA (S-IgA) levels in stimulated salvia were measured before and after a maximal treadmill test in a population of 175 young adults (84 men, 91 women). Habitual physical activity levels of this population were measured by a standardized interview, and scores were obtained for the amount of time and intensity of sports activities and total activity. Before the maximal treadmill test, men and women showed no statistically significant differences in the salivary concentrations of S-IgA, but the concentration of S-IgA in women decreased and in men increased statistically significantly (P less than 0.05) after the treadmill test. Only women showed a significant correlation between absolute values of S-IgA and the weekly amount of time spent on sports activity measured by a standardized interview expressed in minutes per week.     

Development and testing of a short physical activity recall questionnaire

PURPOSE: To develop and test two different short telephone activity recall (STAR) questionnaires, one with closed-ended and the other with open-ended response options, that assessed overall moderate and vigorous activity in a usual week. METHODS: One hundred four participants completed a 3-d test-retest study, and 88 participants completed 10-14, 24-h physical activity recalls (24PAR) and at least 7 d of objective physical activity monitoring by Actigraph during a 28-d period. RESULTS: Consistency of classification from one administration to the next was high (65-92%), extreme inconsistencies between reports were infrequent (0-7%), and kappa values were between 0.50 and 0.75. Correlations between self-reports and criterion measures for moderate-intensity duration were between 0.30 and 0.40. Agreement between the instruments and the 24PAR for meeting the moderate or vigorous recommendations was between 60 and 70%. For the 24PAR comparisons, kappa values tended to be higher for women than men, but were of only modest strength (kappa 0.40). With the 24PAR as criterion, sensitivity of the self-report instruments was between 50 and 90%, and specificity was between 63 and 84%. Kappa values comparing the instruments with the Actigraph were low (<0.20). Overall classification by the short instruments into meeting the recommendations was associated with higher levels of total 24PAR activity (P < or = 0.01) as well as greater steps per day and counts per minute per day from the Actigraph (P < or = 0.08). The open-ended instrument appeared to perform better for moderate-intensity activity, whereas the closed-ended item appeared to perform better for vigorous activity. CONCLUSION: The evaluated instruments had reasonable reliability and demonstrated an ability to capture important differences in overall physical activity patterns in this population, although individual classification errors were substantial.     

Physical activity and body mass index in grade 3, 7, and 11 Nova Scotia students

PURPOSE: This study examined the average time spent in moderate or more intense physical activities according to weight status in randomly selected Nova Scotia students. METHODS: A total of 1653 students participated in this study: 575 in grade 3, 558 in grade 7, and 520 in grade 11. Physical activity was measured for seven consecutive days using MTI accelerometers. Activity counts were classified according to moderate (3-5.9 METs), hard (6-8.9 METs), and very hard (>9 METs) intensities. Height and weight were measured and body mass index (BMI) calculated. Centers for Disease Control and Prevention BMI criteria for age and sex were used to classify the students as normal weight (< or =85th percentile), at risk of overweight (>85th and < or =95th percentiles), and overweight (>95th percentile). ANOVA was used to compare the average time spent in moderate, hard, and very hard physical activities according to BMI status in boys and girls in grades 3, 7, and 11. RESULTS: Although age and sex differences existed, there were no significant differences in the average time spent in moderate or more intense physical activities in the BMI groups. CONCLUSION: Further research is warranted to elucidate the factors surrounding the relationship between physical activity and BMI in children and youths.     

Long-term effects of different physical activity levels on coronary heart disease risk factors in middle-aged men

In order to define the amount of physical activity appropriate in primary prevention of coronary heart disease (CHD), we have compared the effects during 5 years of physical activity in four groups of middle-aged men with different but stable approximate metabolic costs of leisure time sports activities (AMCSA): sedentary (n = 40; 0 kcal per week), low activity (n = 31; 1-999 kcal per week), moderate activity (n = 56; 1,000-1,999 kcal per week), and high activity (n = 71; > or = 2,000 kcal per week). Time related increase of body mass and BMI was more pronounced in lower activity groups. Changes in HDL cholesterol were more favourable in the high activity group as compared to sedentary and low activity groups. The increase of diastolic blood pressure (DBP) in the sedentary group was statistically significantly different from the decrease of DBP observed in both moderate and high activity groups. We conclude that favourable long-term stabilization of most coronary risk factors is achievable with physical activity energy expenditure above 1,000 kcal per week. Physical activity-related energy expenditure > or = 2,000 kcal per week is associated with some additional benefits, especially with a favourable modification of HDL cholesterol level.     

Field evaluation of the Computer Science and Applications, Inc. physical activity monitor

PURPOSE: The purpose of this study was to evaluate the Computer Science and Applications, Inc. (CSA) activity monitor to quantify physical activity in free living subjects using an activity diary as the criterion measure. METHODS: Subjects also completed a 7-d physical activity recall at the end of the monitoring period. Nine male and 10 female subjects (mean, SD) (25.0, 3.6 yr) wore the CSA monitor for 7 consecutive days. On 3 of those days, subjects completed an activity diary (2 weekdays and 1 weekend day). Total kcal per day (Dkcal(tot)) was calculated from the self-reported diary classifications of the subject's activities. For the 3 days that coincided with the diary, total number of counts accumulated per day (cnt(tot)) was obtained from the monitor. RESULTS: The amount of activity per day recorded by the CSA monitor followed the same pattern of change as the activity diary. The cnt(tot) and Dkcal(tot) were significantly (P < or = 0.05) correlated on day 1 (r = 0.65), day 2 (r = 0.49), day 3 (r = 0.55), and for the 3 days pooled (r = 0.51). Subjects were classified as low, moderate, or highly active based on tertiles of kcal from the diary and counts from the CSA monitor. The percentage agreement between the CSA and the activity diary was 68.4% (Kappa = 0.53, P < 0.01). The number of minutes spent in the various activity categories were compared between instruments using an ANOVA model. The results of these analyses suggest that the CSA overestimated light activity and underestimated vigorous activity compared with the diary. CONCLUSION: In conclusion, the CSA monitor may be useful in a field situation where total physical activity and patterns of physical activity are the desired outcomes.     

Physical activity and prevention of type 2 diabetes mellitus

The worldwide prevalence of type 2 diabetes mellitus is increasing at a rapid rate, predominantly because of changes in environmental factors interacting with individual genetic susceptibility to the disease. Data from 20 longitudinal cohort studies present a consistent picture indicating that regular physical activity substantially reduces risk of type 2 diabetes. Adjustment for differences in body mass index between active and inactive groups attenuates the magnitude of risk reduction, but even after adjustment, a high level of physical activity is associated with a 20-30% reduction in diabetes risk. The data indicate that protection from diabetes can be conferred by a range of activities of moderate or vigorous intensity, and that regular light-intensity activity may also be sufficient, although the data for this are less consistent. The risk reduction associated with increased physical activity appears to be greatest in those at increased baseline risk of the disease, such as the obese, those with a positive family history and those with impaired glucose regulation. Data from six large-scale diabetes prevention intervention trials in adults with impaired glucose tolerance or at high risk of cardiovascular disease indicate that increasing moderate physical activity by approximately 150 minutes per week reduces risk of progression to diabetes, with this effect being greater if accompanied by weight loss. However, this level of activity did not prevent all diabetes, with 2-13% of participants per annum who underwent lifestyle intervention still developing the disease. Thus, while 150 minutes per week of moderate activity confers benefits, higher levels of activity may be necessary to maximize diabetes risk reduction in those at high baseline risk of the disease. In contrast, those at low baseline risk of type 2 diabetes, e.g. people with a very low body mass index and no family history of diabetes, will remain at low risk of developing diabetes whether they are active or not. Thus, the amount of physical activity required to confer low risk of diabetes differs according to an individual's level of baseline risk. Consequently, a 'one size fits all' mass-population strategy may not provide the most appropriate approach when designing physical activity guidelines for the prevention of type 2 diabetes. Producing tailored guidelines with the specific aim of reducing risk of diabetes in high-risk populations may provide an alternative approach.     

Reliability and validity of YRBS physical activity items among middle school students

PURPOSE: To assess test-retest reliability and validity of the Youth Risk Behavior Survey (YRBS) items for moderate and vigorous physical activity in middle school students. METHODS: Students (N = 125; 12.7 +/- 0.6 yr) wore Actigraph accelerometers for 6.1 +/- 1.0 d and twice completed surveys that included YRBS moderate and vigorous physical activity items. Accelerometer counts were transformed into minutes of moderate (3-6 METs) and vigorous (> 6 METs) physical activity. Days per week meeting moderate and vigorous physical activity recommendations were estimated using four summary methods. Reliability was assessed using intraclass correlation coefficients (ICC) from the two surveys. Validity was assessed as percent concordance, kappa coefficients, and sensitivity and specificity using binary YRBS and Actigraph outcomes. RESULTS: Test-retest ICC for the moderate and vigorous physical activity items were 0.51 and 0.46, respectively. Twenty-two percent of students met the recommended level of moderate physical activity (>or= 30 min.d(-1), >or= 5 d.wk(-1)) according to self-reports, whereas 90.4 and 66.4% met the recommendation according to accumulated accelerometer minutes and 5-min-bout criteria, respectively. Concordance between YRBS and Actigraph moderate physical activity measures was highest using accumulated accelerometer minutes. Sensitivity of the moderate YRBS item ranged from 0.19 to 0.23 for four comparisons, and specificity was 0.74-0.92. More than two thirds of students reported vigorous physical activity at recommended levels (>or= 20 min.d(-1), >or= 3 d.wk(-1)), whereas the highest prevalence according to Actigraph monitoring was 22.4%. Sensitivity of the YRBS vigorous item was high (0.75-0.92) compared with the four Actigraph measures; specificity was low (0.23-0.26). CONCLUSION: YRBS questions underestimate the proportion of students attaining recommended levels of moderate physical activity and overestimate the proportion meeting vigorous recommendations. Use of accelerometry for physical activity surveillance seems to be indicated. At the minimum, new questions demonstrating greater validity are needed.     

Validation of the RT3 triaxial accelerometer for the assessment of physical activity

PURPOSE: The aims of this study were to assess and compare the validity of the RT3 accelerometer for the assessment of physical activity in boys and men, to compare RT3 and Tritrac accelerometer counts, and to determine count cut-off values for moderate (> or =3 < 6 METs) and vigorous (> or =6 METs) activity. METHODS: Nineteen boys (age: 9.5 +/- 0.8 yr) and 15 men (age: 20.7 +/- 1.4 yr) walked and ran on a treadmill, kicked a ball to and fro, played hopscotch, and sat quietly. An RT3 was worn on the right hip; boys also wore a Tritrac on the left hip. Oxygen consumption was expressed as a ratio of body mass raised to the power of 0.75 (S VO2). RESULTS: RT3 counts correlated significantly with S VO2 in boys (r = 0.87, P < 0.01) and men (r = 0.85, P < 0.01). However, during treadmill activities, RT3 counts were significantly higher for boys (P < 0.05). RT3 counts corresponding to "moderate" and "vigorous" activity were similar for boys and men for all activities (moderate = 970.2 for boys and 984.0 for men; vigorous = 2333.0 for boys and 2340.8 for men) but approximately 400 counts lower in men when only treadmill activities were considered. Tritrac counts correlated significantly with S VO2 in boys (r = 0.87, P < 0.01), but were significantly lower than RT3 counts across most activities (P < 0.05). CONCLUSIONS: The RT3 accelerometer is a good measure of physical activity for boys and men. However, moderate and vigorous intensity count thresholds differ for boys and men when the predominant activities are walking and running. RT3 counts are significantly higher than Tritrac counts for a number of activities. These findings have implications when comparing activity counts between studies using the different instruments.     

长期中等负荷运动对大鼠空间学习记忆及海马神经黏附分子的影响

目的:研究长期中等负荷游泳运动对大鼠空间记忆及海马神经黏附分子(NCAM)的影响。方法:雄性SD大鼠40只,随机分为空白对照组(CN组)、水迷宫组(CM组)、运动组(EN组)和运动+水迷宫组(EM组)4组,每组10只。CN组和CM组常规饲养,不加干预;EN组和EM组进行7周中等负荷游泳训练,1次/天,6 d/周。第1次游10 min,此后每日增加5 min,至第2周末达60 min,第3周后每天游120 min,维持该运动量至第7周。每周末测大鼠体重。7周后,CN组和EN组大鼠断头取大脑海马组织,采用real-time PCR和Western blot检测NCAM mRNA和蛋白表达;CM组和EM组大鼠进行Morris水迷宫训练并检测定其定位航行和空间探索能力。结果:1、实验期间,EN组第5、7周末体重均显著低于CN组(P<0.05);EM组第4、5、6、7周末体重显著低于CM组(P<0.05,P<0.01)。2、Morris水迷宫训练后,EM组大鼠平均逃避潜伏期显著低于CM组(P<0.05),而在水迷宫空间探索实验中,EM组大鼠空间探索平均穿越次数较CM组显著增多(P<0.01)。3、EN组海马组织NCAM基因和蛋白表达均显著高于CN组(P<0.01)。结论:7周中等负荷运动缩短大鼠定位航行逃避潜伏期,提高大鼠空间探索穿越次数,长期适宜运动提高大鼠海马NCAM表达,有利于提高大鼠的空间学习记忆能力。     

Stability and convergent validity of three physical activity assessments

PURPOSE: The purpose of this study was to examine the stability and convergent validity of heart rate (HR) monitoring, Caltrac accelerometer, and physical activity recall (PAR) in sixth-grade girls during normal weekday activities. METHODS: 46 sixth-grade girls (age 12 +/- 0.6) wore HR monitors and Caltrac accelerometers for 3 d during school, after school, and evenings. We also obtained a PAR for each day. Data were compared on the basis of kcal x h(-1). RESULTS: Two days' worth of data were analyzed for each participant. Intraclass correlation coefficients obtained by use of repeated measures ANOVA revealed that HR monitoring (r = 0.99) and PAR (r = 0.98) were extremely stable across 2 d, whereas Caltrac was moderately stable (r = 0.76). Pearson correlations between techniques were HR versus PAR, r = 0.50 (P < 0.01), HR versus Caltrac, r = 0.28, and Caltrac versus PAR, r = 0.76 (P < 0.01). Methods comparison plots showed poor individual subject agreement between all three types of assessment. CONCLUSION: HR and PAR were stable across 2 d. PAR underestimated caloric expenditure by approximately 14%. Caltrac showed the least utility in both reliability and validity.     

Physical activity of moderate intensity in leisure time and the risk of all cause mortality

Background: There are conflicting data about the health benefits of moderately intense physical activity. Objectives: To examine the effect of such activity on all cause mortality in a German sample of men and women. Methods: Physical activity during leisure time of 3742 men and 3445 women aged 30 to 69 was assessed in a baseline questionnaire from 1984 to 1986. The participants were observed during the follow up period until 1998 when a mortality follow up was conducted. Results: During the follow up period, 300 women and 643 men had died. The multivariate rate ratios (RR) for the volume of lifestyle activities of moderate intensity (for example, gardening, walking, cycling) compared with sedentary lifestyle showed a clearly protective dose–response relation (p for trend <0.001) in women but not in men (p for trend 0.20). Following the recommendation for health enhancing physical activity a second analysis was conducted; 2.5 hours per week taking part in physical activity of moderate intensity decreased the relative risk of overall mortality (0.65 (95% confidence interval, 0.51 to 0.82) and 0.90 (0.77 to 1.01) for women and men, respectively). Conclusions: The volume of lifestyle activities of moderate intensity in leisure time was inversely associated with all cause mortality in women but not in men. With regard to the health enhancing physical activity recommendation as a threshold, there were favourable findings only in women.     

Physical activity in the management of obesity in adults: A position statement from Exercise and Sport Science Australia

This Position Statement examines the evidence for physical activity in weight and adiposity loss, prevention of weight and adiposity gain, and in weight regain in adults, and provides guidance on implications for exercise practitioners. Research evidence indicates that >150 min but preferably 300 min per week of aerobic activity of at least moderate intensity is required to prevent weight and adiposity gain, and at least the upper end of this range of activity to prevent weight regain after weight loss. For meaningful weight and total adiposity loss, a minimum of 300–420 min per week of aerobic activity of at least moderate intensity is required. The evidence around the volume of aerobic physical activity required to reduce central adiposity is emerging, and research suggests that it may be substantially less than that required for weight loss. The impact of high-intensity physical activity and resistance exercise for weight management is uncertain. During consultations for weight management, exercise practitioners should advise that metabolic and cardiovascular health benefits can be achieved with physical activity at any weight, and irrespective of weight change.     

Comparison of MTI accelerometer cut-points for predicting time spent in physical activity

The purpose of this study was to establish the accuracy of five published accelerometer regression equations that predict time spent in different intensity classifications during free-living activities. Ten participants completed physical tasks in a field setting for a near-continuous 5 - 6 h-period while oxygen uptake and accelerometer data were collected. The amount of time spent in resting/light, moderate and hard activity was computed from 3 and 6 MET cut-points associated with five existing regression formulas relating accelerometer counts x min -1 to energy expenditure. The Freedson cut-points over-estimated resting/light activity by 34 min (13 %) and under-estimated moderate activity by 38 min (60 %). The Hendelman cut-points for all activities underestimated resting/light activity by 77 min (29 %), and overestimated moderate activity by 77 min (120 %). The Hendelman cut-points developed from walking activities over-estimated resting/light activity by 37 min (14 %) and under-estimated moderate activity by 38 min (60 %). Estimates from the Swartz cut-points for estimating time spent in resting/light, moderate and hard intensity activity were not different from the criterion measure. The Nichols cut-points over-estimated resting/light activity by 31 min (12 %) and under-estimated moderate activity by 35 min (55 %). Even though the Swartz method did not differ from measured time spent in moderate activity on a group basis, on an individual basis, large errors were seen. This was true for all regression formulas. These errors highlight some of the limitations to using hip-mounted accelerometers to reflect physical activity patterns. The finding that different accelerometer cut-points gave substantially different estimates of time spent data has important implications for researchers using accelerometers to predict time spent in different intensity categories.